It's been a miserable winter in Germany. Parts of the country have had 60% fewer sunshine hours than normal. A series of cold snaps have swept the country, reminding all just how expensive heating has become.

Germany's 'Energiewende' (Energy Transition) policy - an intent to be 60% reliable on renewable energy sources for the country's total energy consumption by 2050 - is helping cut costs.

In electricity supply alone, the government is aiming for 80% by 2050, with wind, photovoltaic, bio and hydro energies together already contributing 23% to Germany's electricity consumption in 2012. Some areas are completely self-sufficient.

Some outlets are more than that; policy-makers are examining how houses and towns could distribute their excess or unused energy production more efficiently into the national grid.

"The problem is not the actual production right now, it's the fluctuation of the sources and storing the excess energy intelligently," says Tobias Rothacher, Senior Manager of Renewable Energies at Germany Trade and Invest.

Photovoltaic sources are not much use in winter, but there's no way yet found of saving the energy produced in summer and using those reserves in winter. There's no solar energy piggy bank for a rainy day.

"Distributed stationary energy storage is the hottest topic in the Renewable Energy industry right now, which makes Dusseldorf's Energy Storage Convention on March 18 of huge global interest, for it is not just Germany striving to solve this problem," concluded Rothacher.